1. Field of the Invention
The present invention relates to a door opening and closing apparatus that opens and closes a sliding door of a vehicle such as a railway vehicle.
2. Description of Related Art
Conventionally, a door opening and closing apparatus is known that can perform both opening/closing and locking a door with a single motor, using a planetary gear (e.g., JP2008-121242 A). This door opening and closing apparatus includes a lock mechanism that mechanically restricts movement of the door in an opening direction such that the door in a fully closed state is not brought into an opened state by error. The door can thereby be prevented from moving in the opening direction even if a motor enters a free state due to a malfunction or the like, when the door is in the fully closed state.
In the lock mechanism illustrated in FIG. 11 in JP2008-121242 A, as disclosed in paragraph 0073 of JP2008-121242 A, a connecting pin (projecting shaft) fixed to a bottom face portion of a lock slider moves together with the lock slider in a locking direction and an unlocking direction. This projecting shaft is in a state where portions thereof on the locking direction side and the unlocking direction side are sandwiched by a pair of projecting portions formed at a center link in a link mechanism. In this state, the center link rotates as a result of the projecting shaft moving in the locking direction and the unlocking direction, and therefore the lock mechanism is switched between a locked state and an unlocked state.